I co-own a Catalina 25 with a fixed keel. The draft of the boat is 4 feet. The boat weighs about 4,500 pounds. The trailer has pressure brakes (the forward momentum of the trailer compresses the brake piston when the towing vehicle slows down). The pressure brakes on the trailer make a big difference when stopping.
We've towed our boat several hundred miles with no problem. We use a Ford 150 pickup to pull the boat. The mast lays with one end on the bow pulpit and the other end on a mast crutch that is lashed to the stern pulpit. We support the mast in the middle with a crutch that sits on the mast step and compression post.
The boat and trailer are shorter in height, shorter in length, and narrower than a standard truck trailer, so we've never had to secure a permit to tow the boat. It fits under most bridges. The tallest point of the boat on its trailer is a little under 12 feet. The standard height of a truck trailer is around 13 and a half feet so most bridges have a clearance of at 14 or more feet. Off the interstate, you will want to pay close attention to the posted clearance height of bridges.
One consideration is getting the boat into the water. Most launch ramps are not steep enough to float a fixed keel boat with a 4 foot draft while the trailer is attached to the truck because the truck has to get too deep in the water before the boat floats. With the trailer positioned on the slope of the ramp, we block the wheels of the trailer, detach the trailer from the truck, and then attach a heavy duty tow strap. We didn't trust the wheel on the tongue jack so we made a kind of spare tire carrier that swings down and uses the spare tire to supports the tongue while the trailer rolls backwards. Once the strap attaches the trailer to the truck, we pull forward and remove the wheel chucks. The weight of the boat and trailer is enough that the trailer rolls down the ramp incline into water deep enough to float the boat. The truck and two strap keep the trailer from going too far or too fast. You have make sure that the ramp continues far enough. Many ramps end with a drop-off and you don't want the rear trailer tire to go over the drop-off.
Another consideration is keeping the boat on the trailer (our trailer has rollers that support the boat while underway). We use two heavy straps with ratchets to strap the boat to the trailer. The trailer has a vertical beam at the front of the trailer. The beam has a winch and a bow-nest at the end. We attach the winch cable to the bow-eye of the boat and lock the winch with plenty of tension on the cable. The beam seems strong enough to keep the boat from rolling forward or aft during standard braking and acceleration.
A final consideration is trailer brakes. Before we took our boat on the highway, we rebuilt the braking system. The original master and slave cylinders were all frozen with rust. With the new cylinders and with careful adjustment of the brakes, the boat and trailer seem to put almost no forward pressure on the truck when braking. Note that if you try to back up a steep hill or accelerate backwards sharply, the pressure may activate the brakes.
